Petzl Reverso - Green

Reverso Features:

Multipurpose and easy to use:
Classic belay technique with both hands on the rope
Ropes glide smoothly through the device
Can be used for rappels
Reverso mode for belaying one or two seconds; commonly used on multi-pitch climbs
Independent and simultaneous belaying of two seconds in Reverso mode
While belaying in Reverso mode, a carabiner placed in the release hole allows the belayer to give slack when the device is under tension
Rope installation diagrams for belaying and Reverso mode are engraved on the device
Adapted to a broad range of rope diameters:
V-shaped friction grooves enable controlled braking 
Compatible with dynamic single ropes 8.5 to 10.5 mm (11 mm possible, depending on the rope's suppleness) 
Compatible with dynamic half ropes 7.1 to 9.2 mm
Compatible with dynamic twin ropes 6.9 to 9.2 mm
Durable and lightweight:
The rounded design of the rope slots limits wear and extends the life of the device
Compact and lightweight: only 57 g